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  #1  
Old 04-23-2013
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Question LP or Antibiotics for Meningitis?

Can anyone answer these two questions please. They are very similar.

The first question is from MTB step 3 (2012)

1. A 5 month old child presents with lethargy, poor feeding, and irritability. He has been vomiting for 2 days and has had a temperature of 101. 3 deg F. On exam, the fontanelles are noted to be bulging, and there is paralysis of lateral gaze on the left side. The mother reports that he is up-to-date on all vaccinations. Which of the following is the next step in management?

a. CT scan of the head
b. Empiric antibiotics
c. Lumbar Puncture
d. Steroids
e. Urine Culture

The second question is from UWORLD


2. An eight month old is brought to the emergency department by his mother because of vomiting and a decreased urine output. He was seen by his paediatrician 3 days ago because of fever, sore throat and ear pain. He was subsequently diagnosed with otitis media and treated with oral amoxycillin. His temp is 40 deg C (104 deg F), BP is 100/60, pulse is 90 and respirations are 40 per min and irregular. He weighs 8 kg. He is lethargic and rouses to only painful stimuli. Examination shows that anterior fontanelle is full and tense and tympanic membranes are red and bulging. His pupils are reactive but his eyes do not focus well on his parents. Which of the following is the next best step in managment?

a. Lumbar puncture followed by intravenous ceftriaxone and vancomycin
b. IV ampicillin followed by lumbar puncture
c. CT scan of brain followed by lumbar puncture
d. MRI of brain followed by lumbar puncture
e. Intravenous ceftriaxone and vancomycin followed by lumbar puncture

please explain.
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Old 04-23-2013
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1. b)empiric antibiotics----as there is contraindication to LP----lateral gaze palsy(any clear neurological deficit is C/I to LP)

2. A) LP followed by antibiotics


p.s----in adults with meningitis---first give empiric antibiotics then LP
in children with meningitis----first LP then antibiotics ,unless LP C/I

hope it clears..
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Old 04-23-2013
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thanks

But isn't raised ICP a contraindication too? Both the patients have bulging fontanelles which equal raised ICP don't they? And its the explanation for both the answers that confused me.

In the first question, MTB says the same thing.. that raised ICP is a contraindication to LP as it might cause brainstem herniation.

But in the second question, the UWORLD answer says that in infants less than 1 year of age, it is safe to do LP even with raised ICP as the open fontanelle protects against brainstem herniation.

Can you explain which answer is correct?
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Quote:
Originally Posted by wertheworld11 View Post
thanks

But isn't raised ICP a contraindication too? Both the patients have bulging fontanelles which equal raised ICP don't they? And its the explanation for both the answers that confused me.

In the first question, MTB says the same thing.. that raised ICP is a contraindication to LP as it might cause brainstem herniation.

But in the second question, the UWORLD answer says that in infants less than 1 year of age, it is safe to do LP even with raised ICP as the open fontanelle protects against brainstem herniation.

Can you explain which answer is correct?
i think both are correct imo......infants cant get classic neurologic signs(nuchal rigidity,kernig sign etc) as adults...so they manifest as bulging fontanelle,jitteriness etc..
yes, raised ICP is C/I ,but sometimes we can use it to reduce ICP too...
and regarding the point in uworld-----infants less than 1yr is safe----->i.e the reason in infants treatment is LP followed by antibiotics

thanks for your doubts.....i gotta chance to revise it.....hope it clears
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Old 04-23-2013
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I still don't understand how these two questions have different answers.

They should both have the same answer (either antibiotics due to contraindication of increased ICP, or LP because they're less than a year old and the contraindication doesnt apply to them), right?
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yes, C/I doesnt apply for increased ICP to both of them for doing LP ...but baby 1 has neurological deficit too----paralysis of lateral gaze(which in my opinion C/I for LP) ....
but wait for any other valid explanations too
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Default A bulging fontanelle in the absence of other signs is not a CI to LP in children

Signs of raised icp
Drowsy
Abnormal pupillary responses
Unilateral or bilateral motor posturing
Papilledema,but papilledema
Is an unreliable and late sign of raised icp in meningitis
And lastly bulging fontanelle in the absence of other signs is not a contraindications of L P in children,I think it can be a explanation,
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Old 04-23-2013
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Here are the official answers

1. Answer is B. This history is highly suggestive of meningitis. However, the patient is also exhibiting signs of increased ICP, a contraindication to LP (workup of meningitis included blood culture and LP, unless there are signs of raised ICP). CT scan is not sensitive in diagnosing increased ICP or meningitis. It is not required for initiation of antibiotics when clinical suspicion is high. The most important next step in management is to begin empiric antibiotics based on clinical suspicion. Intravenous dexamethasone has been shown to be of value in management of meningitis due to HiB. However, HiB is uncommon in the United States with the advent of vaccines, which protect against HIB infections.


2. Answer is A. The first step in management should be supportive with oxygen and fluids, blood culture and appropriate admission blood tests. In contrast to suspected meningitis in adults, in whom antibiotics are followed by CT scan and LP, children should have an LP and then antibiotics. An LP is quick and easy to obtain in most children even if they are agitated. Herniation is a very unlikely possibility in children < 1 year of age as the fontanelles have not yet closed. This patient should have an LP followed by Dexamethasone, vancomycin and a third generation cephalosporin. If LP is unsuccessful or cannot be performed then antibiotics should be given and LP obtained as soon as possible.

@Venky I guess you are right in saying that in adults, the Antibiotics should be given first and in children LP should be done first. But what about raised ICP in children, is it a contraindication or not?
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Quote:
Originally Posted by wertheworld11 View Post
Here are the official answers

1. Answer is B. This history is highly suggestive of meningitis. However, the patient is also exhibiting signs of increased ICP, a contraindication to LP (workup of meningitis included blood culture and LP, unless there are signs of raised ICP). CT scan is not sensitive in diagnosing increased ICP or meningitis. It is not required for initiation of antibiotics when clinical suspicion is high. The most important next step in management is to begin empiric antibiotics based on clinical suspicion. Intravenous dexamethasone has been shown to be of value in management of meningitis due to HiB. However, HiB is uncommon in the United States with the advent of vaccines, which protect against HIB infections.


2. Answer is A. The first step in management should be supportive with oxygen and fluids, blood culture and appropriate admission blood tests. In contrast to suspected meningitis in adults, in whom antibiotics are followed by CT scan and LP, children should have an LP and then antibiotics. An LP is quick and easy to obtain in most children even if they are agitated. Herniation is a very unlikely possibility in children < 1 year of age as the fontanelles have not yet closed. This patient should have an LP followed by Dexamethasone, vancomycin and a third generation cephalosporin. If LP is unsuccessful or cannot be performed then antibiotics should be given and LP obtained as soon as possible.

@Venky I guess you are right in saying that in adults, the Antibiotics should be given first and in children LP should be done first. But what about raised ICP in children, is it a contraindication or not?

thanks for posting answers......

this is the doubt i have too.........increased ICP a contraindication of LP-----------but looking at the statement of uworld---- 'Herniation is a very unlikely possibility in children < 1 year of age as the fontanelles have not yet closed.'--i think LP can be performed ,if no obvious ICP signs are seen in the pt...

but now i i'm confused here again.....will post again ,if i get clear with it.....
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  #10  
Old 04-24-2013
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dude ,just studied kaplan peds meningitis topic-------increased ICP is C/I to LP----> signs of increased ICP--bulging ant.fontanelle, 3rd or 6th cranial nerve palsy,emesis,hypertension with brady(if you have time refer it pg.244)

and also checked in wiki regarding bulge ant fontanelle--->it's an indicator for increased ICP but not specific----as prolonged cry of baby also increase ICP..

hope this helps
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Old 04-24-2013
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Quote:
Originally Posted by venky2600 View Post
dude ,just studied kaplan peds meningitis topic-------increased ICP is C/I to LP----> signs of increased ICP--bulging ant.fontanelle, 3rd or 6th cranial nerve palsy,emesis,hypertension with brady(if you have time refer it pg.244)

and also checked in wiki regarding bulge ant fontanelle--->it's an indicator for increased ICP but not specific----as prolonged cry of baby also increase ICP..

hope this helps
Let me summarize what I learnt from this discussion.

a. In any patient (adult or child) with suspected meningitis, do LP first before and start antibiotics (if LP is not contraindicated)

b. If LP is contraindicated, we need to do CT scan first to rule out raised ICP.
the contraindications to immediate LP: i. papilledema, ii. focal neurological signs iii. seizures iv. confusion (because neurological examination cannot be done).

c. If CT needs to be done, then immediated IV antibiotics should be started.

d. In young infants, bulging fontanelle is not a contraindication to immediate LP but focal neurological findings are.

am I correct? Need to add or modify anything?
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Old 04-24-2013
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all are correct ,except 1. in adults---empiric antibiotics(vanco+ceftriaxone+steroids) are given prior to CT or LP
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